Flame resistant unsaturated polyester composition containing an organic antimony compound



FLAME RESISTANT UNSATURATED POLYESTER COD/[POSITION CONTAINING AN ORGANIC AN- Tlll IONY COMPOUND Blaine 0. Schoepfie and Burton S. Marks, Niagara Falls, and Paul Robitscheh, Wilson, N.Y., assignors to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of New York No Drawing. Application October 4, 1957 Serial No. 688,144

11 Claims. (Cl. 260-485) This invention relates to flame resistant polyester compositions and more particularly to such compositions containing organic flame-retarding agents soluble therein.

Synthetic resins such as polyester resins have found wide-spread use throughout industry, in ever increasing amounts. However, one of the most formidable deterrents to an even greater development has been their tendency to ignite and burn when placed in contact with a flame. The general trend of the research devoted to this problem has been toward the goal of producing a composition which, although it may still bum when held in a flame, will extinguish itself when the flame is removed.

Various methods have been used by experimenters in the field to diminish the flammability of the polyester resin. One method has been to introduce combined halogen into the polyester molecule itself. One example of this is the polyester formed by first producing the hexachlorocyclopentadiene adduct of maleic anhydride and esterifying it in the presence of an additional amount of maleic anhydride with a glycol such as ethylene glycol, after which the polyester may be cross-linked by any of the common cross-linking agents such as styrene, in the presence of a polymerization catalyst. This method has resulted in a material which has a very high degree of flame resistance. Other polyesters have been made utiliz ing :tetrachlorophthalic anhydride as the acid component of the polyester molecule.

Another method for producing a flame resistant polyester composition has been to provide a physical mixture of a non-halogen containing polyester with a chlorinated parafiin Wax. This has increased the flame resistance of the composition materiall although not to the degree enjoyed by the combined-chlorine-containing polyester resins, but has done this to the detriment of other desirable properties.

Some of these compositions, especially the combinedhalogen-containing, such as chlorine-containing polyesters have been found suitable for a great many purposes where flame-resistance is desirable. However, for some uses, such as in the building trades, it has been found desirable to increase the flame-resistance of the polyester resin even to a higher degree than that already possessed by even the combined-halogen-containing polyesters. In order to accomplish this, as disclosed in copending application Serial No. 450,217, filed August 16, 1954, it was found effective to incorporate a small amount of antimony trioxide into the polyester resin. This succeeded in increasing flame-resistance over that of the chlorinated polyester or the chlorinated paraflin wax-containing polyester alone. However, it was found that the introduction of antimony trioxide into these polyesters rendered the final molded product made from same almost opaque, rendering them useless for applications where a transparent finished product or one having a high degree of light transmission was desired.

It is an object of the present invention to provide a polyester resin composition which has a very high degree Patented Nov. 17, 1959 ice of flame-resistance. It is a further object of this invention to provide a flame-retarding agent which will increase the flame-resistance of both halogen-containing and non-halogen containing polyester resins. It is a further object of this invention to provide a flame-retarding agent which will increase the flame-resistance of chlorinated paraffin wax containing polyester resins. It is a further object of this invention to provide such flame-retarding agents which do not appreciably diminish the light transmission of the cured polyester composition. It is a further object of this invention to provide such a flame-retarding agent which will not inhibit the final polymerization and cure of the polyester resin composition to the extent that it renders its use impractical. Further objects and advantages of this invention will appear more fully'from the following description.

It has now been found that the flame-resistance of polyester resin compositions which contain copolymerizable unsaturation, said compositions also containing either combined chlorine within the polyester molecule or within the cross-linking agent therein or both or which contain an admixture of a combined-chlorine-containing additive may be rendered even more flame-resistant in the finally cured state, while at the same time retaining their light transmitting properties, by the incorporation into such compositions prior to the curing process, of an organic antimony compound which is soluble therein and which has the formula:

wherein R, R and R" are aryl radicals, Sb is pentavalent antimony, and X is a monovalent radical selected from the group consisting of chloride, fluoride, hydroxide, an alcoholate, an organic acid radical, and mixtures thereof, and wherein 2X together is oxygen.

Among such organic acid radicals which are included in our invention are benzoates, acetate, caprylate, etc.

Among such alcoholate groups which are included in our invention are methoxy, ethoxy, propoxy, butoxy, benzoxy, etc.

It has further been found that the fiame resistance of even non-chlorine-containing polyesters may also be improved by the flame retarding agents of the present invention.

It has also been found that the incorporation of the soluble antimony compounds of the present invention does not appreciably diminish the light transmitting properties of the cured polyester resin. This is an important factor where the cured products are to be used in the building trades, where high light transmission is desired for many applications.

The halogen-containing polyester compositions, such as chlorine-containing, which may be utilized in the present invention fall generally within two different classes. In the first class the halogen is chemically combined in the polyester molecule itself, or in the cross-linking monomer or both. The second class contains those compositions where no chlorine is chemically combined in the polyester, but, chlorine is introduced into the precured resin either by way of an additive such as chlorinated wax or one of the chloiine-containing additives of this invention, or both.

This classification does not preclude the possibility of utilizing an admixture of both the first and second class with the additives of this invention in order to obtain an improved fire-resistant resin.

'i'iitofthree 'difieie'iit "types or chlorine-containing poly ester compositions. In the first type the halogen, e.g. chlorine isipresent in the form of a chlorinated adduct of the polycarboxylic acid, anhydride or alcohol. One example of this type is l,4,5,6,7,7-hexachlorobicyclo inhibit the polymerization to even a gelled state. ysis by one percent by weight of benzoyl peroxlde '(2 percent by weight of Luperco A.T.C. which is 50 per- 2.:2.1)-5 heptene2,3-dicarboxyiic anhydride, which is V theadduct'for'rned by reacting about'equimolar amounts of 'hexachlorocyclopentadiene' with "maleic anhydride. This is then esterified -with a glycol in the presence of additional maleic anhydiide and finally cured in the presenceof a polymerizable ethylenically unsaturated monomer such as styrene in the presence of a polymerization Catalyst. Another example of the first type of the first class is the polyester resin 'producedffr'o'm maleic anhydride, the'adduct of hexachlorocyclo' ions with hutene diol, and "cured inithepresence of styieneli. The second type of the first class is the composition where the polybasic acid itself is Chlorinated. An example of this is the polyester which comprises the reaction product of tetrachlo'rophtha'licanhydride with a glycol in the presence 'of'an additional unsaturated acid to provide double bondsfor cross-linking, a polymeriz able monomer such as styrene and a polymerizationbatalyst. I

The third type of the first class comprises polyester compositions which containa chlorinated cross-linking agent. Among such chlorinated cross-linking agents are -the various chlorinated styrenes, 'e.g. mono, di and tri chlorostyrenes and certain adducts of hexahalocyclo pentadiene.

cent benzoyl peroxide and 50 percent tricresyl phosphate), one percent by weight of commercial methylethylketone peroxide catalyst, one percent by weight of commercial ter't-butyl hydroperoxide, etc., all provedun successful in curing the resin. The polymerization inhibiting'etfect of this material is demonstrated by Example l9. I i

The flame-retarding agent of the present invention is used in amounts of at elast about 0.5 percent by weight of the total polyester composition. Three percent :has a very, appreciable eflect in making the composition more flame-resistant. Five percent of the additive in most cases will impart excellent flame resistance. 7 As much "as ten percent or even moremay be used where extremely high flame-resistance is desired. However, when a very large percentage'of the flame retardant agent is used the product might become very expensive and may ,sufier deterioration in some of its physical properties;. therefore, prudence in selecting the amount is recommended.

The compositions of the second class which contain 'the chlorine combined in the additive or filler, can be illustrated by the composition comprising the reaction product of phthalic anhydride, maleic anhydride, a glycol, to which is added a chlorinatedparafiin wax, styrene, and apolymerization catalyst.

- The flame-retarding agents of the present invention we are defined by the formula:

wherein R, R" and R are aryl radicals, Sb is pentavalent antimony, and X is a monovalent radical selected from the group consisting of chloride, 'fluoride, hy-

droxide, an alcoholate, an organic acid radical, and

tures thereof. R, R and R" may be either different or' the same radicals. Among the'compounds which'may be used as the flame-retarding agent are triphenylstibine difiuoride, triphenylstibine dichloride, triphenylstibine dibenzoate, tritolylstibinedichloride, triphe'nylstibine hydroxide cuinylate, tritolylstibine difiuoride, tritolylstibine diacetate, tritolylstibine dibenzoate, 'triphenylstibine dimethylate, ortho, para, and meta hydroxy isomers of either triphenylstibine dichloride, triphenyl stibine diiluoride, triphenylstibine diacetate, and triphenylstibine dibenzoate and mixtures thereof.

The antimony must be present in its pentavalent form since triaryl substituted trivalent, antimony compounds have an inhibiting efiiect upon the free 'radical polymerization or cure of the polyester compositions of this invention.

stibine when included 'as a three percent (by weight) additive in the various polyesters of this invention would It was found for example that triphe'nyl The fire resistance imparting agents of the present invention may be incorporated in any method known to the art, and are generally incorporated by physical mix ing with the liquid polyester composition. The composition may then be cured in the normal manner. 7

In the following examples which are given to further illustrate this invention, parts are given on-a weight basis unless otherwise specified, and the examples are not intended to limit the invention except as defined inthe appended claims. 1

Example '1 illustrates the preparation of a polyester resin wherein the polycarboxylic compound portion of same is the hexachlorocyclopentadiene adduct of maleic acid: a

Example J-.-An unpolymerized liquid unsaturated V polyester resinwas prepared by esterifying about 159 parts of ethylene glycol with'about 389 parts of 1,4,5, 6,7,7 .hex'achlorobicyclo (2.2.1) 5 heptene 2,3- dicarboxylic acid (which was prepared. by the Diels' Alder reaction of hexachlorocyclopentadiene with maleic ..}anhydride and then hydrolyzed), 152 partsof adipic acid and 61' parts of furnaric acid; About 40 parts of'styrene" and about 100 parts of the product produced by the esterification-reaction were mixed together until complete solution was attained to give a clear, substantially colorless solution of liquid polyester resin'having a vis'- gelled and cured at 50 degrees centigrade for 24 hour-s and then'post-cured at degrees centigrade for atleast cosity of about 10 poises at 25 degrees centigrade on long as a precipitate formed. The triphenylstibine 'di chloride so prepared was then recrystallized and dried.

Table '1 below indicates the results of flame retardance' tests according to ASTM 'D75749'on samplescut from,

cylindrical castings made from a resin prepared in the manner of Example 1 into which the indicated amounts" of triphenylstibine dichloride as prepared above in Ex: ample 2 had been added and mixed. In each case two percent (by weight) of Luperco ATC catalyst (a mixture of fifty percent benzoyl peroxide and fifty percent tricresyl phosphate) was incorporated into the mixture.

The castings for tests were prepared by passing the liquid resin mix containing the flame-resistant agent into 8 mm. diameter glass tubes, after which the material was first 15 hours.

Catal- TABLE I Flame retardance of castings (per ASTM D-757-49) The following Examples 6 and 7 illustrate the preparation and use in polyester compositions of the triarylstrbine dibenzoates as exemplified by triphenyl stibine dibenzoate.

Example 6.--A mixture of 10.6 grams (0.03 mole) of tripheriylstibine, 7.3 grams (0.03) mole of benzoyl peroxide, and 200 cc. of normal hexane were heated for approximately one hour. The white shiny crystalline precipitate was filtered ofi to yield 13.6 grams (76%) of triphenylstilbine dibenzoate. The corrected melting point was 174177 degrees centigrade. The literature reports a melting point of 1705-1735 degrees centigrade (F Challenger and V Wilson, Journal of Chemical Society, 209 (1927)). Recrystallization from benzene, petroleum ether gave a melting point of 172.5-173 degrees centigrade.

Example 7.Into three hundred grams of the resin prepared in Example 1 was added nine grams or 3 percent by weight of tripheriylstibine dibenzoate. The mixture was heated slightly and stirred on a steam bath in order to insure solution. After cooling, six grams or 2 percent by weight of Luperco ATC (50 percent benzoyl peroxide and 50 percent tricresyl phosphate) was added and stirred into the solution. The cure was carried out by first heating a bath maintained at 50 degrees centigrade for 24 hours, followed by heating in an oven maintained at 80 degrees centigrade for 24 hours,, to yield a clear transparent resin. This resin was self-extinguishing and had an ASTM D757-49 burning rate of 0.19 inch per minute as compared to 0.52 inch per minute in the control (Example 3).

Examples 8 and 9 following, illustrate the preparation and use in polyester compositions of the triarylstibine diacetates, as exemplified by tripheriylstibine diacetate.

Example 8.-Triphenylstibine diacetate was prepared as follows according to the method of H Schmidt, Ann. 429, 142 (1922): Triphenylstibine dihydroxide is dissolved in hot acetic acid and allowed to stand over night. On cooling, tripheriylstibine diacetate separated out and was filtered off. The purified material had a melting point of 215 C.

Example 9.-Nine grams or 3 percent by weight of triphenylstibine diacetate produced above were mixed together with 300 grams of the resin prepared in a manner after that described in Example 1. The mixture was heated and stirred on the steam bath to effect solution. After cooling, six grams or 2 percent by weight of a mixture of Luperco ATC (50 percent benzoyl peroxide and 50 percent tricresyl phosphate) were added and stirred into the solution. The resin was cured as in Example 7 above. A clear transparent flame-proof resin resulted. This resin was self-extinguishing and had an ASTM D757-49 burning rate of 0.19 inch per minute as compared to 0.52 inch per minute in the control.

Example 10 following illustrates the preparation of and use in polyester compositions of tripheriylstibine dialcoholate as exemplified by triphenyl stibinedimethylate.

Example 10.--Into 40 ml. of anhydrous methanol was placed 2.7 g. (0.05 m.) of sodium methylate and 12.8 g. (0.025 m.) of tripheriylstibine dibromide. The reaction mixture was kept at reflux for 2 hours after which time 5 ml. of dry toluene was added and the reaction mixture allowed to reflux for 15 hours more.

The mixture was cooled to yield a white precipitate. Addition of water to the filtrate yielded further product. Included in the product with tripheriylstibine dimethylate was some of the half adduct triphenyl stibine methylate bromide. The product requires no further purification for use in the resin.

Nine grams or 3 percent by Weight of product produced above were mixed together with 300 g. of the resin prepared in the manner after that described above. The mixture was heated and stirred on the steam bath to effect solution. After cooling, six grams or 2 percent by weight of a mixture of Luperco ATC (50 percent benzoyl peroxide and 50 percent tricresyl phosphate) were added and stirred into the solution. The resin was cured as in Example 7 above. A clear transparent flameproof resin resulted. This resin was self extinguishing and had an ASTM D757-49 burning rate of 0.20 inch per minute as compared to 0.52 inch per minute in the control.

Example 11 following illustrates the preparation of and use in polyester compositions of a derivative of triarylstibine as exemplified by tripheriylstibine dihydroxide.

Example 11.Into ml. of cyclohexane Was placed 10.6 g. (.03 m.) of tripheriylstibine and 6.25 g. (0.03 m.) of 73% cumylhydroperoxide was added dropwise. There was an immediate exothermic reaction on addition and copious White precipitate was noted to form as the reaction progressed. The reaction was allowed to stir overnite. The product was filtered and washed with cyclohexane and dissolved in benzene. Stripping off of the solvent yielded tripheriylstibine dihydroxide, a white precipitate, M.P. 215 C. corrected.

Nine grams or 3 percent by weight of product produced above were mixed together with 300 gms. of the resin prepared in a manner after that described above in Example 1. The mixture was heated and stirred on the steam bath to effect solution. After cooling, six grams or 2 percent by weight of a mixture of Luperco ATC (50 percent benzoyl peroxide and 50 percent tricresyl phosphate) were added and stirred into the solution. The resin was cured as in Example 7 above. A clear, transparent, flame-proof resin resulted. The resin was self-extinguishing and had an ASTM D757-49 burning rate of 0.19 inch per minute as compared to 0.52 inch per minute in the control.

Although the foregoing examples, all of which are typical of the first type of the first class of compositions previously described have emphasized the product resulting from the use of the adduct of hexachlorocyclopentadiene with maleic anhydride, other adducts of hexahalocyclopentadiene may be used, among which are the following: 1,4,5,6,7,7-hexachloro-2-methylbicyclo- (2.2.1)-5-heptene-2,3-dicarboxylic anhydride, said compound and its method of preparation being disclosed and claimed in copending application Ser. No. 308,924, filed September 10, 1952, now U.S. Patent No. 2,779,769, involving the reaction of hexachlorocyclopentadiene with citraconic anhydride; the mono-methyl ester of 1,4,5,6, 7,7 hexachlorobicyclo-(2.2. l -5-heptene2,3-dicarboxylie acid, said compound being prepared by the method involving the reaction of hexachlorocyclopentadiene with maleic anhydride followed by esterification of the adduct so produced with the amount of methanol required to produce the mono-methyl ester; 3-(1,4,5,6,7,7-hexachlorobicyelo-(2.2.l)-5 heptene-Zyl methoxy1,2-propanediol, said compound and its method of preparation being described in copending application Ser. No. 309,922, filed September 10, 1952, involving the reaction to hexachlorocyclopentadiene with alpha allyl glycerol ether; 1,4,5 ,7 tetrachloro-6,7-difluorobicyclo-( 2.2.1 -5-heptene- 2,3-dicarboxylic acid, said compound and its method of preparation being disclosed and claimed in copending application Ser. No. 308,934, filed September 10, 1952,

now abandoned, involving 'the reaction of 1,2;4,5-tetrachloro-l,3-difluorocyclopentadiene with maleicanhydride; 1,4,5 ;6,.7,7 -ihexachlorobicyclo-(2.2.1 --'heptene-2-acetic- 2-carboxylic anhydride, said compound audits method of preparation being disclosed and claimed in copending application Ser. No. 308,923, filed September 10, 1952, now U.S. Patent No. 2,752,361, involving the reaction of .hexachlorocyclopentadiene with itaconic anhydride'; and 1,4,5 ,6,7,7-hexachlorobicyclo-( 2.2.1 -5 -heptene-2,3- di'car'bonyl chloride; said compound and its method of preparation being disclosed and claimed in copending application Ser. No. 450,216, filed August 16, 1954, now US. Patent No. 2,812,347, involving the reaction of hexachlorocyclopentadiene with fumaryl chloride.

7 Various other adducts of hexahalocyclopentadiene may also be' employed particularly in the cross linking agent, such as: .diallyl-1,4,5,6,7,7-hexachlorobicyclo- (252.1) 5-heptene-2,3-dicarboxylate: diallyl-l,4,5,6,7,7-

-hexachloro 2 methylbicyclo-'(2.2.1)-5-heptene-2,3-di

carboxylate; diallyl 1,2,4,5,6,7,7' heptachlorobicyclo (2.2.1)-5-heptene-2,3-dicarboxylate; and triallyl-1,4,S,6,7,

7 hexachlorobicyclo-(2.2.1)-S-heptene-Z-acetate-2,3 -dicarboxylate. These. compounds'can be prepared byreacting hexachlorocyclopentadiene with the indicated dicarboxylic acid and esterifying the resultant product with an unsaturated alcohol such as allyl alcohol;

Still other adducts-of hexahalocyclopentadiene may be employed, for instance, the adducts formed with: unsaturated polycarboxylic acids such as, fumaric, itaconic, acetylene dicarboxylic and esters and halogen'substituted derivatives thereof, etc.; unsaturated polyhydric alcohols such 'as, butene-diol, -etc.; also unsaturated'hydroxy ethers such as, allyl or vinyl glycerol ethers, allyl orvinyl pentaerythritol ethers, etc.; and still other chemical com pounds comprising an ethylenicor an acetylenic linkage which'are not rendered unreactive in the polyester chain by their chemical combination-into the polyester chain by way: of other functional groups.

The following Examples 12 and 13typify the second typeof the first class of polyester compositions'previously described and illustrate the benefit of using an additive 1 of the present invention with a polyester 'resin comp'osition where theacid component of the ester is directly chlorinated. :Each of the resins of these examples were madebymixing 100 parts of a-tetrachloropht-halic" anhydride basedstyrenated polyester resin with twoperce nt by weight of a mixture of percent benzoyl peroxide and 50 percent tricresylphosphate. The resin use'd was a clear, light-amber-colored, thick liquid having a slight odor and having a viscosity at 25 degrees centigra'deof 3700-4400 centipoises; it has a' specific gravity or 1-.270

1.280 at'25 degrees centigrade and its refractive index at; this temperature is 1.5566; it has n styrene; content of 28.0 percent and an acidnurnber of 17 -19. Example 12 V is the control and Example 13 uses thedesignated antimony additive. Curing was obtained by first heating in a bath maintained at.50 degrees centigrade for 24 hours followed by heating in an oven'maintained at approximately 80-90 degrees centigrade for 24 hours. The'catalyst and curingconditions set forth above were used throughout in preparing the finally cured resinsi'of this invention;

7 V Sb additive, 'ASTM D757-49 No. Resin, 100 parts 3 parts Burning-Rate, in. per min.

12 Tetrachlorophthalic anhy- Nonentni 0. 32

dride based resin. 7 18;" lo Triphenylstibine 0'25 Dichloride.

Q The following Examples :14 and '15 typifyingthethird type of the first class of compositions previously-dc scribed, illustrate the advantage to-be= obtained byadding and curing in the manner previously described, a flame w retarding agent of the "present "invention with polyester resins which do not themselves contain. combined chlorine, but in which however the cross-linking agent is chlorinated. The polyester resin used in both of these 7 examples was the same and was a'phthalic acid, maleic anhydride, ethylene glycol, based resin with dichlorostyrene used'as the cross-linking agent. The data shows the properties obtained.

v Additive Ex. in parts N 0. Flame Retarding Agent per hundred of resin ASTM 13757-49 Burning Rates, in. per min.

14 None 0. 59 15. 'Triphenylstibine dibenz oate 3 0. 41

The following Examples 16, 17 and 18, 'typifyingtlie second class of compositions previously described, illus- A-STM D635-44, inches per min.

Ex. Sb Ad- No. Resin, parts ditive;

I fi parts f' lhe' followin g modifications of ASTM procedure D635-44 were used for the evaluations:

(1) No wire gauze was used under the sample.

'(2) The time of burning was taken from the end of'the sample to a point three inches from the same end.

(3) Samples 0.1 inch thick were used.

The above table shows that the addition of a small amount of triphenylstibinef dichloride to a non-chlorinecontaining polyester will itself considerably'improve the flame-resisting properties. However, when the triphenylstibine dichloride is used in conjunction with a'fire retardant additive such as chlorinated'wax, the flame-resisting properties are improved to an even greater extent.

. All the resins in the above examples were transparent, as well. as flame-resistant, in contrast to those composi-. tions produced by using antimony trioxide which are opaque.

The following example demonstrates as'previously discussed that the presence of triphenyl stibine inhibits the polymerization of the polyester resin.

Example 19.In a large casting test tube were placed the following ingredients: 100 grams polyester resin of Example 1, 3 grams triphenyl stibine, and 2 grams of Luperco ATC (50 percent benzoyl peroxide and 50 percent tricresyl phosphate). The'test tube was placed in a 50 C. bath; howeverafter 48 hours no gelation could be noted. .Also raising the temperature to 80 C. and maintaining it for 24=hours did not cause gelation of'the resin.

The polymeriza'ble unsaturation of the polyesters of this invention maybe obtained by introducing in'to -th'e' poly-' ester chain a reactive unsaturated chemical'ingredient whichxis capable of rendering the polyester co'polymerizable even after his in'chemical combinationin'the poly ester molecule. :A particularly suitable materialfor this e s maleic anhydride; however any unsaturated polycarboxylic compound, such as substituted or unsubstituted acids, anhydrides and acide halides, or polyhydric alcohols, or, esters thereof, containing a plurality of esterifiable groups, and capable of estcrification without losing its ability to copolymerize with olefinic cross-linking agents may be employed.

Another method of providing for copolymerizable unsaturation in the polyester chain which may be employed involves: effecting the diene synthesis of hexachlorocyclopentadiene with a polybasic alcohol or acid or ester, or equivalents thereof, which contains at least two olefinic linkages, one of which is reactive in the diene synthesis, while the others which are unreacted, are capable of being copolymerizable in the cross-linking reaction. Among the materials which are useful for this purpose are acetylenic compounds and di-olefinic and poly-olefinic compounds. n 7,

Having thus described our invention, what we claim and desire to secure by Letters Patent is:

1. A polymerizable mixture comprising (A) a polymerizable unsaturated polyester of ingredients comprising (1) a polycarboxylic compound and (2) a polyhydric alcohol; (B) an ethylenically unsaturated monomer copolymerizable with (A), and (C) a flame retardant agent having the formula:

wherein R, R and R" are aryl radicals, Sb is pentavalent antimony, X is a monovalent radical selected from the group consisting of chloride, fluoride, hydroxide, alkoxy, benzoxy, benzoate, aliphatic carboxylate, and mixtures thereof, and wherein said flame retarding agent is soluble in the mixture of (A) and (B) and is present in an amount at least about 0.5 percent by weight of A and B.

2. A mixture according to claim 1, wherein a portion of said polycarboxylie compound (1) comprises the adduct of hexahalocyclopentadiene and a polycarboxylic compound containing aliphatic carbon to carbon unsaturation, wherein the halogen is selected from the group com sisting of chlorine, bromine, fluorine and mixtures there of.

3. A mixture according to claim 1, wherein a portion of said polyhydric alcohol (2) comprises the adduct of hexahalocyclopentadiene and a polyhydric alcohol containing aliphatic carbon to carbon unsaturation, wherein the halogen is selected from the group consisting of ch10 rine, bromine, fluorine and mixtures thereof.

4. A mixture according to claim 2 wherein the adduct is 1,4,5,6,7,7-hexachlorobicyclo (2.2.1) 5-heptene-2,3- dicarboxylic acid.

5. A mixture according to claim 2 wherein the adduct is 1,4,5,6,7,7-hexachlorobicyclo(2.2.1)-5-hrptene-2,3-dicarboxylic anhydride.

6. A mixture according to claim 1 wherein a portion of said polycarboxylic compound (1) comprises tetrachlorophthalic anhydride.

7. A mixture according to claim 1 wherein said copolymen'zable ethylenically unsaturated monomer is selected from the group consisting of styrene and dichlorostyrene.

8. A mixture according to claim 1 having a minor proportion of a chlorinated parafiin wax added thereto.

9. A mixture according to claim 1 when polymerized to an infusible, insoluble state.

10. A mixture according to claim 1 wherein the substituent X in the flame retardant agent (C) is a chlorine radical.

11. A mixture according to claim 1 wherein the substituents R, R and R" in the flame retardant agent (C) are the same radical.

References Cited in the file of this patent UNITED STATES PATENTS 2,299,612 Clayton et al. Oct. 20, 1942 2,413,163 Bacon Dec. 4, 1946 2,420,644 Athy et al. May 20, 1947 2,566,208 Jenkins Aug. 28, 1951 2,640,000 Seyb et al. May 26, 1953 OTHER REFERENCES Ind. and Eng. Chem., vol. 46, No. 8, August 1954, pages 1628-1632.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,913,428 November 17, 1959 Blaine O. Schoepfle et al- It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 12, for "elast" read least column 6, line 69, for "Ser. No. 309,922" read Ser. No. 308,922 line 70 for "reaction f0" read reaction of column 9 line 2,, for "acide" read acid Signed and sealed this 26th day of July 1960.

( S EAL) Attest:

KARL H. AXLINE Attesting Officer ROBERT c. WATSON Commissioner of Patents UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No, 2,913,428 November 17f 1959 Blaine O. Schoepfle et a1.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 4, line 12, for "elast" read least column 6 line 69 for "Ser. No. 309,922"- read S er. No. 308,922 ---7; line 7O- for "reaction f0" read reaction of column 9 line 2, for "wide" read acid Signed and sealed this 26th day of July 1960.

(SEAL) Attest: R

KARL H. AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner of Patents 

1. A POLYMERIZABLE MIXTURE COMPRISING (A) A POLYMERIZABLE UNSATURATED POLYESTER OF INGREDIENTS COMPRISING (1) A POLYCARBOXYLIC COMPOUND AND (2) A POLYHYDRIC ALCOHOL; (B) AN ETHYLENICALLY UNSATURATED MONOMER COPOLYMERUZABLE WITH (A), AND (C) A FLAME RETARDENT AGENT HAVING THE FORMULA: 